Genetic dissection of Brassica napus seed vigor after aging.

KEY MESSAGE: Stable and novel QTLs that affect seed vigor under different storage durations were discovered, and BnaOLE4, located in the interval of cqSW-C2-3, increased seed vigor after aging. Seed vigor is an important trait in crop breeding; however, the underlying molecular regulatory mechanisms governing this trait in rapeseed remain largely unknown. In the present study, vigor-related traits were analyzed in seeds from a doubled haploid (DH) rapeseed (Brassica napus) population grown in 2 different environments using seeds stored for 7, 5, and 3 years under natural storage conditions. A total of 229 quantitative trait loci (QTLs) were identified and were found to explain 3.78%-17.22% of the phenotypic variance for seed vigor-related traits after aging. We further demonstrated that seed vigor-related traits were positively correlated with oil content (OC) but negatively correlated with unsaturated fatty acids (FAs). Some pleiotropic QTLs that collectively regulate OC, FAs, and seed vigor, such as uq.A8, uq.A3-2, uq.A9-2, and uq.C3-1, were identified. The transcriptomic results from extreme pools of DH lines with distinct seed vigor phenotypes during accelerated aging revealed that various biological pathways and metabolic processes (such as glutathione metabolism and reactive oxygen species) were involved in seed vigor. Through integration of QTL analysis and RNA-Seq, a regulatory network for the control of seed vigor was constructed. Importantly, a candidate (BnaOLE4) from cqSW-C2-3 was selected for functional analysis, and transgenic lines overexpressing BnaOLE4 showed increased seed vigor after artificial aging. Collectively, these results provide novel information on QTL and potential candidate genes for molecular breeding for improved seed storability.

Causal relationship between gut microbiota and diabetic nephropathy: a two-sample Mendelian randomization study.

Objective: Emerging evidence has provided compelling evidence linking gut microbiota (GM) and diabetic nephropathy (DN) via the "gut-kidney" axis. But the causal relationship between them hasn't been clarified yet. We perform a Two-Sample Mendelian randomization (MR) analysis to reveal the causal connection with GM and the development of DN, type 1 diabetes nephropathy (T1DN), type 2 diabetes nephropathy (T2DN), type 1 diabetes mellitus (T1DM), and type 2 diabetes mellitus (T2DM). Methods: We used summary data from MiBioGen on 211 GM taxa in 18340 participants. Generalized MR analysis methods were conducted to estimate their causality on risk of DN, T1DN, T2DN, T1DM and T2DM from FinnGen. To ensure the reliability of the findings, a comprehensive set of sensitivity analyses were conducted to confirm the resilience and consistency of the results. Results: It was showed that Class Verrucomicrobiae [odds ratio (OR) =1.5651, 95%CI:1.1810-2.0742,PFDR=0.0018], Order Verrucomicrobiales (OR=1.5651, 95%CI: 1.1810-2.0742, PFDR=0.0018) and Family Verrucomicrobiaceae (OR=1.3956, 95%CI:1.0336-1.8844, PFDR=0.0296) had significant risk of DN. Our analysis found significant associations between GM and T2DN, including Class Verrucomimicrobiae (OR=1.8227, 95% CI: 1.2414-2.6763, PFDR=0.0139), Order Verrucomimicrobiae (OR=1.5651, 95% CI: 1.8227-2.6764, PFDR=0.0024), Rhodospirillales (OR=1.8226, 95% CI: 1.2412-2.6763, PFDR=0.0026), and Family Verrucomicroniaceae (OR=1.8226, 95% CI: 1.2412-2.6763, PFDR=0.0083). The Eubacteriumprotogenes (OR=0.4076, 95% CI: 0.2415-0.6882, PFDR=0.0021) exhibited a protection against T1DN. Sensitivity analyses confirmed that there was no significant heterogeneity and pleiotropy. Conclusions: At the gene prediction level, we identified the specific GM that is causally linked to DN in both T1DM and T2DM patients. Moreover, we identified distinct microbial changes in T1DN that differed from those seen in T2DN, offering valuable insights into GM signatures associated with subtype of nephropathy.

3D genome structural variations play important roles in regulating seed oil content of Brassica napus.

Dissecting the complex regulatory mechanism of seed oil content (SOC) is one of the main research goals in Brassica napus. Increasing evidence suggests that genome architecture is linked to multiple biological functions. However, the effect of genome architecture on SOC regulation remains unclear. Here, we used high-throughput chromatin conformation capture to characterize differences in the three-dimensional (3D) landscape of genome architecture of seeds from two B. napus lines, N53-2 (with high SOC) and Ken-C8 (with low SOC). Bioinformatics analysis demonstrated that differentially accessible regions and differentially expressed genes between N53-2 and Ken-C8 were preferentially enriched in regions with quantitative trait loci (QTLs)/associated genomic regions (AGRs) for SOC. A multi-omics analysis demonstrated that expression of SOC-related genes was tightly correlated with genome structural variations in QTLs/AGRs of B. napus. The candidate gene BnaA09g48250D, which showed structural variation in a QTL/AGR on chrA09, was identified by fine-mapping of a KN double-haploid population derived from hybridization of N53-2 and Ken-C8. Overexpression and knockout of BnaA09g48250D led to significant increases and decreases in SOC, respectively, in the transgenic lines. Taken together, our results reveal the 3D genome architecture of B. napus seeds and the roles of genome structural variations in SOC regulation, enriching our understanding of the molecular mechanisms of SOC regulation from the perspective of spatial chromatin structure.

Genome-scale targeted mutagenesis in Brassica napus using a pooled CRISPR library.

The recently constructed mutant libraries of diploid crops by the CRISPR-Cas9 system have provided abundant resources for functional genomics and crop breeding. However, because of the genome complexity, it is a big challenge to accomplish large-scale targeted mutagenesis in polyploid plants. Here, we demonstrate the feasibility of using a pooled CRISPR library to achieve genome-scale targeted editing in an allotetraploid crop of Brassica napus A total of 18,414 sgRNAs were designed to target 10,480 genes of interest, and afterward, 1104 regenerated transgenic plants harboring 1088 sgRNAs were obtained. Editing interrogation results revealed that 93 of the 178 genes were identified as mutated, thus representing an editing efficiency of 52.2%. Furthermore, we have discovered that Cas9-mediated DNA cleavages tend to occur at all the target sites guided by the same individual sgRNA, a novel finding in polyploid plants. Finally, we show the strong capability of reverse genetic screening for various traits with the postgenotyped plants. Several genes, which might dominate the fatty acid profile and seed oil content and have yet to be reported, were unveiled from the forward genetic studies. Our research provides valuable resources for functional genomics, elite crop breeding, and a good reference for high-throughput targeted mutagenesis in other polyploid plants.

Dissecting the Meiotic Recombination Patterns in a Brassica napus Double Haploid Population Using 60K SNP Array.

Meiotic recombination not only maintains the stability of the chromosome structure but also creates genetic variations for adapting to changeable environments. A better understanding of the mechanism of crossover (CO) patterns at the population level is useful for crop improvement. However, there are limited cost-effective and universal methods to detect the recombination frequency at the population level in Brassica napus. Here, the Brassica 60K Illumina Infinium SNP array (Brassica 60K array) was used to systematically study the recombination landscape in a double haploid (DH) population of B. napus. It was found that COs were unevenly distributed across the whole genome, and a higher frequency of COs existed at the distal ends of each chromosome. A considerable number of genes (more than 30%) in the CO hot regions were associated with plant defense and regulation. In most tissues, the average gene expression level in the hot regions (CO frequency of greater than 2 cM/Mb) was significantly higher than that in the regions with a CO frequency of less than 1 cM/Mb. In addition, a bin map was constructed with 1995 recombination bins. For seed oil content, Bin 1131 to 1134, Bin 1308 to 1311, Bin 1864 to 1869, and Bin 2184 to 2230 were identified on chromosomes A08, A09, C03, and C06, respectively, which could explain 8.5%, 17.3%, 8.6%, and 3.9% of the phenotypic variation. These results could not only deepen our understanding of meiotic recombination in B. napus at the population level, and provide useful information for rapeseed breeding in the future, but also provided a reference for studying CO frequency in other species.

The emerging role of pyroptosis in pediatric cancers: from mechanism to therapy.

Pediatric cancers are the driving cause of death for children and adolescents. Due to safety requirements and considerations, treatment strategies and drugs for pediatric cancers have been so far scarcely studied. It is well known that tumor cells tend to progressively evade cell death pathways, which is known as apoptosis resistance, one of the hallmarks of cancer, dominating tumor drug resistance. Recently, treatments targeting nonapoptotic cell death have drawn great attention. Pyroptosis, a newly specialized form of cell death, acts as a critical physiological regulator in inflammatory reaction, cell development, tissue homeostasis and stress response. The action in different forms of pyroptosis is of great significance in the therapy of pediatric cancers. Pyroptosis could be induced and consequently modulate tumorigenesis, progression, and metastasis if treated with local or systemic therapies. However, excessive or uncontrolled cell death might lead to tissue damage, acute inflammation, or even cytokine release syndrome, which facilitates tumor progression or recurrence. Herein, we aimed to describe the molecular mechanisms of pyroptosis, to highlight and discuss the challenges and opportunities for activating pyroptosis pathways through various oncologic therapies in multiple pediatric neoplasms, including osteosarcoma, neuroblastoma, leukemia, lymphoma, and brain tumors.

Lysophosphatidic acid acyltransferase 2 and 5 commonly, but differently, promote seed oil accumulation in Brassica napus.

BACKGROUND: Increasing seed oil content (SOC) of Brassica napus has become one of the main plant breeding goals over the past decades. Lysophosphatidic acid acyltransferase (LPAT) performs an important molecular function by regulating the production of phosphatidic acid (PA), a key intermediate in the synthesis of membrane and storage lipids. However, the mechanism underlying the effect of LPAT on the SOC of B. napus remains unclear. RESULTS: In the present study, significant elevation of SOC was achieved by overexpressing BnLPAT2 and BnLPAT5 in B. napus. RNAi and CRISPR-Cas9 were also successfully used to knock down and knock out these two genes in B. napus where SOC significantly decreased. Meanwhile, we found an accumulation of lipid droplets and oil bodies in seeds of BnLPAT2 and BnLPAT5 overexpression lines, whereas an increase of sugar and protein in Bnlpat2 and Bnlpat5 mutant seeds. Sequential transcriptome analysis was further performed on the developing seeds of the BnLPAT2 and BnLPAT5 overexpression, knockdown, and knockout rapeseed lines. Most differentially expressed genes (DEGs) that were expressed in the middle and late stages of seed development were enriched in photosynthesis and lipid metabolism, respectively. The DEGs involved in fatty acid and lipid biosynthesis were active in the overexpression lines but were relatively inactive in the knockdown and knockout lines. Further analysis revealed that the biological pathways related to fatty acid/lipid anabolism and carbohydrate metabolism were specifically enriched in the BnLPAT2 overexpression lines. CONCLUSIONS: BnLPAT2 and BnLPAT5 are essential for seed oil accumulation. BnLPAT2 preferentially promoted diacylglycerol synthesis to increase SOC, whereas BnLPAT5 tended to boost PA synthesis for membrane lipid generation. Taken together, BnLPAT2 and BnLPAT5 can jointly but differently promote seed oil accumulation in B. napus. This study provides new insights into the potential mechanisms governing the promotion of SOC by BnLPAT2 and BnLPAT5 in the seeds of B. napus.

Further insight into decreases in seed glucosinolate content based on QTL mapping and RNA-seq in Brassica napus L.

KEY MESSAGE: The QTL hotspots determining seed glucosinolate content instead of only four HAG1 loci and elucidation of a potential regulatory model for rapeseed SGC variation. Glucosinolates (GSLs) are amino acid-derived, sulfur-rich secondary metabolites that function as biopesticides and flavor compounds, but the high seed glucosinolate content (SGC) reduces seed quality for rapeseed meal. To dissect the genetic mechanism and further reduce SGC in rapeseed, QTL mapping was performed using an updated high-density genetic map based on a doubled haploid (DH) population derived from two parents that showed significant differences in SGC. In 15 environments, a total of 162 significant QTLs were identified for SGC and then integrated into 59 consensus QTLs, of which 32 were novel QTLs. Four QTL hotspot regions (QTL-HRs) for SGC variation were discovered on chromosomes A09, C02, C07 and C09, including seven major QTLs that have previously been reported and four novel major QTLs in addition to HAG1 loci. SGC was largely determined by superimposition of advantage allele in the four QTL-HRs. Important candidate genes directly related to GSL pathways were identified underlying the four QTL-HRs, including BnaC09.MYB28, BnaA09.APK1, BnaC09.SUR1 and BnaC02.GTR2a. Related differentially expressed candidates identified in the minor but environment stable QTLs indicated that sulfur assimilation plays an important rather than dominant role in SGC variation. A potential regulatory model for rapeseed SGC variation constructed by combining candidate GSL gene identification and differentially expressed gene analysis based on RNA-seq contributed to a better understanding of the GSL accumulation mechanism. This study provides insights to further understand the genetic regulatory mechanism of GSLs, as well as the potential loci and a new route to further diminish the SGC in rapeseed.

Ketogenic diet in women with polycystic ovary syndrome and liver dysfunction who are obese: A randomized, open-label, parallel-group, controlled pilot trial.

AIM: To evaluate the effect of a ketogenic diet (KD) in women with polycystic ovary syndrome (PCOS) and liver dysfunction who were obese. METHODS: Women with PCOS and liver dysfunction who were obese were enrolled in this prospective, open-label, parallel-group, controlled pilot trial, and randomly received KD (KD group) or conventional pharmacological treatment (Essentiale plus Yasmin, control group) in a 1:1 ratio for 12 weeks. The primary endpoint was the liver function markers. Secondary endpoints included the menstrual cycle, anthropometric characteristics, body composition, hormonal levels, and metabolic biomarkers. RESULTS: Of the 20 eligible participants enrolled, 18 participants completed the study. The KD group reported a significant reduction in anthropometric characteristics and body composition from baseline to week 12 (all p < 0.05). In addition, there were significant reductions in menstrual cycle, plasma estradiol, and progesterone levels in two groups (all p < 0.05), but no significant between-group difference was observed. KD significantly reduced the liver function markers compared with control group (p < 0.05). The signs of fatty liver disappeared in six out of seven fatty liver participants in KD group after 12 weeks of intervention, while only one of 10 fatty liver participants in control group disappeared. CONCLUSIONS: In addition to improving the menstrual cycle, KD had the additional benefits of reducing blood glucose and body weight, improving liver function, and treating fatty liver compared to traditional pharmacological treatment in women with PCOS and liver dysfunction who were obese.

The complete mitochondrial genome of Xenophysogobio nudicorpa (Cypriniformes; Cyprinidae).

In this study, the complete mitochondrial DNA genome sequence of Xenophysogobio nudicorpa was first determined by DNA sequencing based on the PCR fragments. The complete mitochondrial DNA (mtDNA) genome sequence of X. nudicorpa is a circular molecule of 16,616 bp in length. It consists of 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and a control region (D-loop). The gene nucleotide composition of X. nudicorpa is 30.5% A, 26.0% C, 16.8% G, and 26.7% T, with a relatively high A+T content (57.2%). The results could provide useful data for studying genetic diversity and phylogenetics in X. nudicorpa and related species.

The complete mitochondrial genome of Platysmacheilus nudiventris (Teleostei, Cyprinidae, Gobioninae).

The complete mitochondrial genome of Platysmacheilus nudiventris (Teleostei, Cyprinidae, Gobioninae), an endemic Chinese cyprinid fish, was first determined by DNA sequencing based on the PCR fragments. The total length of the mitochondrial genome is 16,603 bp, including 22 transfer RNA genes, 2 ribosomal RNA genes, 13 protein-coding genes and a non-coding control region (D-loop). The overall-based composition is 30.2% A, 26.9% T, 16.7% G and 26.1% C, with high A+T content (57.1%). The results will provide useful data for further studies on species identification, evolutionary and population genetic studies of P. nudiventris and its related species.

The complete mitochondrial genome of Sinibrama taeniatus (Cyprinidae: Cultrinae).

In this study, the complete mitochondrial DNA genome sequence of Sinibrama taeniatus was first determined by DNA sequencing based on the PCR fragments. The complete mitochondrial DNA (mtDNA) genome sequence of S. taeniatus was a circular molecule of 16,623 bp in length. It consisted of 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and a control region (D-loop). The gene nucleotide composition of S. taeniatus was 31.3% A, 26.8% C, 16.1% G, and 25.8% T, with a relatively high A + T content (57.1%). The results could provide useful data for studying genetic diversity and phylogenetics in S. taeniatus and related species.

The complete mitochondrial genome of Pseudobagrus emarginatus (Siluriformes: Bagridae).

In this study, the total mitochondrial genome sequence of Pseudobagrus emarginatus (Siluriformes: Bagridae) was firstly sequenced and determined. The complete mtDNA genome sequence of P. emarginatus is 16,534 bp in length. It consists of 22 transfer RNA genes, 2 ribosomal RNA genes, 13 protein-coding genes, and a non-coding control region (D-loop). The overall-based composition was 31.5% A, 26.8% T, 14.9% G and 26.8% C, with a high A+T content (58.3%), which was nearly the same as other reported catfishes. These results will provide useful data to the natural resources conservation and systematics analysis of P. emarginatus and its related species in future.

The complete mitochondrial genome of Rhinogobio typus (Teleostei, Cyprinidae, Gobioninae).

In the present study, the complete mitochondrial genome sequence of Rhinogobio typus (Teleostei, Cyprinidae, Gobioninae) was obtained using a PCR-based method. The total length of the mitochondrial genome is 16,608 bp, including 22 transfer RNA genes, 2 ribosomal RNA genes, 13 protein-coding genes, and a non-coding control region (D-loop), which is similar to that observed in many other reported fishes. The overall-based composition is 31.3% A, 26.6% T, 15.9% G and 26.2% C, with high A + T content (57.9%). These results will provide a useful tool for species identification, evolutionary and population genetic studies of R. typus and its related species.

Complete mitochondrial genome of Pareuchiloglanis sinensis (Siluriformes: Sisoridae).

The complete mitochondrial genome of Pareuchiloglanis sinensis, an endemic Chinese sisorid fish, was determined by DNA sequencing based on the PCR fragments. The complete mtDNA genome sequence of P. sinensis is 16,593 bp in length, with a gene content of 13 protein-coding, 2 ribosomal RNA, and 22 transfer RNA genes, and a typical gene arrangement identical to many other reported fishes. The overall base composition of the heavy strand was 30.6% A, 24.2% T, 16.0% G and 29.2% C, with a relatively high A + T content (54.8%). This will provide a useful tool for understanding the genetic diversity, population structure and conservation status of P. sinensis in future.

The complete mitochondrial genome of Glyptothorax sinense (Siluriformes, Sisoridae).

Glyptothorax sinense (Siluriformes, Sisoridae), is a kind of small-sized freshwater fish which mainly distributes in the middle and upper reaches of the Yangtze River in China. In this study, the complete mitochondrial genome of G. sinense was first determined using a PCR-based method. The complete mtDNA sequence is 16,531 bp in length, including 22 transfer RNA genes, 2 ribosomal RNA genes, 13 protein-coding genes, and a non-coding control region (D-loop). The overall-based composition was 31.61% A, 26.66% T, 15.38% G and 26.34% C, with a relatively high A + T content (58.27%). This will provide a useful tool for evolutionary and population genetic studies of G. sinense.